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Biomedical subjects

J F Liu

Publications and source records attributed to J F Liu.

At least 73 records · Page 4Linked to original sources

Multilamellar hydrodissection in phacoemulsification and planned extracapsular surgery.

Multilamellar hydrodissection is the injection of balanced salt solution into multiple lamellae of the lens, cleaving it into a small nucleus and multiple layers of cortex. In phacoemulsification, the smaller nucleus reduces phacoemulsification time, and the thicker bed of cortex provides greater protection for the posterior capsule. In extracapsular extraction, the smaller nucleus can be more readily extracted, which is particularly advantageous when capsulorhexis is performed. Creation of multiple cortical lamellae facilitates their aspiration, either with the phacoemulsification or irrigation/aspiration tips. Multilamellar hydrodissection increases the predictability and safety of phacoemulsification and planned extracapsular cataract extraction.

Cataract Extraction↗

Survey of the clinical use of glare and contrast sensitivity testing.

In August 1988, we surveyed a random 10% sample of the members of the American Society of Cataract and Refractive Surgery about their use of contrast sensitivity and glare testing. Of 396 surveys mailed, 214 were returned for a response rate of 54.3%. Thirty-six percent of respondents used glare testing alone; 5.6% used contrast sensitivity testing alone; 23.4% used both test modalities; 35% used neither. The most common uses of glare and contrast sensitivity testing were to evaluate visual function in patients who have cataracts, secondary cataracts, and/or intraocular lens problems.

Cataract↗

[Relation between myocardial ultrastructural and serum enzymatic changes before and after intracardiac operations].

The serum GOT, CPK, LDH of 18 patients with heart disease were determined at pre- and postoperative periods. At postoperative period all the three serum enzymes were increased apparently (P less than 0.001). Slight to moderate myocardial ultrastructural damages were observed postoperatively in 10 cases. The degree of myocardial injure was correlated with the rising levels of the serum enzymes. This suggested that the change of the three enzymes may be utilized as a reference index of degree of myocardial injure.

Aspartate Aminotransferases↗

[Protective effects of total saponins of semen Ziziphi spinosae on cultured rat myocardial cells].

The effects of total saponins of Semen Ziziphi spinosae (ZS) were observed on cultured neonatal rat myocardial cells injured by deprivation of oxygen and glucose (DOG) or treatment with chlorpromazine (CPZ) and mitomycin C (MMC). The increases of lactate dehydrogenase release from damaged myocardial cells induced by DOG, CPZ and MMC were attenuated by ZS (33 micrograms/ml) except 11 micrograms/ml which showed no effect on MMC (24 h) and CPZ (9 h)-induced injuries. These data suggest that ZS is an effective protective drug for myocardial cells.

Animals↗

Refractive complications of cataract surgery after radial keratotomy.

Four patients underwent cataract extraction with posterior chamber lens implantation several years after radial keratotomy. All four patients experienced an initial hyperopic shift caused by an early postoperative corneal flattening of greater than or equal to 1 diopter. This flattening partially regressed, leaving the patients with a mean of 0.42 diopter of persistent corneal flattening. We found the Binkhorst and the Holladay intraocular lens calculation formulas to be more accurate than the SRK II for these patients. Corneal curvature measured with the keratometer was less accurate for intraocular lens calculations than was a value derived by subtracting the refractive change induced by the radial keratotomy from the patients' keratometric measurements obtained before radial keratotomy.

Cataract Extraction↗

Axial myopia increases the risk of retinal complications after neodymium-YAG laser posterior capsulotomy.

We conducted a retrospective analysis of Q-switched neodymium-YAG laser capsulotomies performed in 122 eyes between April 1984 and June 1987. Retinal complications occurred in 3 (2.5%) of 121 eyes followed up for 1 year and in 2 (3.6%) of 55 eyes followed up for 2 years. Four eyes developed rhegmatogenous retinal detachments and 1 developed an acute symptomatic retinal tear. No patients developed clinical cystoid macular edema (visual acuity 20/30 or worse). These retinal complications were significantly correlated with axial myopia, preexisting vitreoretinal disease, male gender, younger age, vitreous prolapse into the anterior chamber, and spontaneous extension of the capsulotomy.

Adolescent↗

Conformational characterization of a single-site mutant of murine epidermal growth factor (EGF) by 1H NMR provides evidence that leucine-47 is involved in the interactions with the EGF receptor.

Epidermal growth factor (EGF) is a small protein containing 53 amino acids and three disulfide bonds. There is significant current interest in structure-function relationships in EGF and EGF-like proteins, including the homologous type-alpha transforming growth factors. The Leu-47 residue of murine EGF (mEGF) is one of several that are strongly conserved among the EGF-like growth factors, suggesting that it may contribute to the active site of mEGF. In several different binding assays, the activity of the mutant analog in which Leu-47 is replaced by Ser [( Ser47]mEGF) ranges from 8 to 18 times weaker than that of wild-type mEGF. The NMR data summarized in this paper demonstrate that the significant differences in the binding activities of wild-type and [Ser47]mEGF cannot be attributed to structural changes remote from the three-dimensional site of mutation. The only minor conformational changes that are indicated by these data involve side chains of residues proximal to Leu-47 in the three-dimensional structure. Therefore, Leu-47 and/or residues spatially adjacent to Leu-47 constitute part of the active site of mEGF.

Animals↗

Structure-function studies of murine epidermal growth factor: expression and site-directed mutagenesis of epidermal growth factor gene.

Wild-type murine epidermal growth factor (mEGF) and mutants with Leu47 replaced by serine and valine, respectively, have been produced by recombinant DNA methodology. A synthetic gene for mEGF was fused to the coding sequence for the signal peptide of the outer membrane protein A (ompA) of Escherichia coli in the secretion vector pIN-III-ompA3, and the recombinant plasmid was used to transform E. coli. Upon induction of gene expression, mEGF and the mutants was expressed and secreted into the periplasmic space. Purification of the wild-type Leu47-mEGF and the mutants was carried out by reversed-phase and anion-exchange high-performance liquid chromatography (HPLC). Amino acid analysis and Western blot analysis further confirmed the identities of the proteins. Specific activities for wild-type and mutant proteins were measured in both mEGF receptor binding and autophosphorylation assays. The recombinant mEGF has specific activities identical with that of mEGF purified from mouse submaxillary glands, while both mutants have reduced specific activities in both bioassays. The data demonstrate the importance of the highly conserved Leu47 residue in mEGF for full biological activity.

Amino Acid Sequence↗

Complications of implanting three-piece C-loop posterior chamber lenses in the anterior chamber.

We have examined a total of four eyes in three patients who had undergone implantation of three-piece C-loop posterior chamber intraocular lenses into the anterior chamber. All four eyes exhibited four or more of the following complications: 1) loop encapsulation by peripheral anterior synechiae; 2) recurrent iritis; 3) central loop displacement with corneal endothelial touch; 4) progressive endothelial cell loss and corneal edema; 5) glaucoma; and 6) cystoid macular edema. Intraocular lens removal was required in all four eyes, and penetrating keratoplasty was performed in one. We believe that these complications are attributable to the inherent fallacies of fixating three-piece open-loop lenses in the anterior chamber angle.

Aged↗

In vivo induction of malignant transformation of nude mouse B lymphocytes by a human multiple myeloma.

The bone marrow puncture fluid of human multiple myeloma was inoculated subcutaneously in BALB/C/nu nude mice. After passage of the xenograft from nude mice in vitro, a murine malignant lymphosarcoma cell line was unexpectedly established, which was named NLB-SK. The murine NLB-SK cell line has been cultivated in vitro over 72 passages for 10 months. Repeated cryopreservation showed that the murine NLB-SK cell line revived satisfactorily. Based on cell biological characteristics the malignant transformation might be attributed to horizontal oncogenesis between human malignant tumor cells and nude mouse normal somatic cells.

Animals↗

Polymorphism of glycophorins in nonhuman primate erythrocytes.

Using immunoblotting techniques and polyclonal antisera to human erythrocyte alpha glycophorin, we show that erythrocytes of several species of nonhuman primates, including representatives of anthropoid apes (19 chimpanzees, 3 gorillas, 6 orangutans, and 3 gibbons) and Old World monkeys (3 baboons, 5 rhesus monkeys, and 6 cynomolgus macaques), contain human alpha glycophorin-like molecules. Each species displays a unique glycophorin profile; in anthropoid apes the profile is more complex than in Old World monkeys and more similar to that seen in humans. The chimpanzee was the only species in which human delta-like glycophorin was detected but it differed from its human counterpart in electrophoretic mobility and reaction with M-specific monoclonal antibody. In contrast to humans, highly polymorphic glycophorin profiles were observed in each species of anthropoid apes and three distinct patterns were defined in each. No such polymorphism has been found so far among the Old World monkeys in the limited number of animals studied. The major glycophorins in all species but the chimpanzees failed to react with M- or N-specific monoclonal antibodies, suggesting structural differences from the human within the amino terminal regions. The reaction with the minor glycophorins showed inter- and intraspecies variability. All glycophorins, except delta-like glycophorin in the chimpanzee, reacted with the antiserum to the carboxyl terminal fragment of human alpha glycophorin, indicating a structural relation to the human in this region. An unexpected correlation was observed, in the chimpanzee, between the patterns of electrophoretically resolved glycophorins and the V-A-B-D blood-group phenotypes, allowing the assignment of each determinant to specific glycophorin bands. The basis for the differences observed between human and nonhuman primate glycophorins is not clear but the possibilities include a common nonpolymorphic ancestor and differences in selective pressures.

Animals↗